System for controlling the motion of electrically-operated elevators by means of a switch.



- 11117111111311 FEB. 11, 1908. W. BAXTER, JR. THE 11011011 OF ELEGTRIOALLY OPERATED SYSTEM POR CONTROLLING ELEVATORS BY MEANS OF A SWITOH.

APPLICATION FILED MAY 21.1902.

18 SHEETS-SHEET l INVEJVTOR WITNESSES No. 878,496. PATENTED FEB. 11, 1908. W. BAXTER, JR.

SYSTEM FOR CONTROLLING THE MOTION OF ELEOTRIOALLY OPERATED ELEVATORS BY MEANS OF A SWITCH.

APPLICATION FILED MAY 21.1902.

18 SHEETS-SHEET 2.

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N0. 878 496. W. BAXTER JR. PATENTED FEB. 11, 1908 SYSTEM FOR CONTROLLING THE MOTION OF ELEOTRIOALLY OPERATED ELEVATORS BY MEANS OF A SWITCH, APPLICATION FILED MAY 21. 1902.

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SYSTEM FOR CONTROLLING ELEVATORS APPLIO PATENTED FEB 11, 1908. W. BAXTBR, 1R.

THE MOTION OF ELEGTRIOALLY OPERATED BY MEANS OF A SWITCH. ATION FILED MAY 21, 1902.

18 SHEETSSHEET 4.

WI T .NESSE S (fl W 5- W I.7\'"VENTOR N0. 878,496. PATENTED FEB. 11, 1900. W. BAXTER, 1B. SYSTEM FOR CONTROLLING 111511011011 OF 51001111011111 OPERATED ELEVATORS BY MEANS OF A SWITCH.

1 APPLICATION FILED MAY 21.1002.

18 SHEETS-SHEET 5 WITNESSES INVENTOR 1W flm ff Wm M 2m PATENTED FEB. 11 1908. W. BAXTER, JR.

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SYSTEMiFOR CONTROLLING THE MOTION 015 ELECTRIC BY MEANS OF'A SWITCH.

ALLY OPERATED \ELBVATORS APPLICATION FILED MAY 21. 1902.

cm T E E H s S T E E H S 8 1 JIN'V'EMFOR .IITTYS' WITNES ES No. 878,496. PATENTED PEB.'11, 1908. W. BAXTER, JR.

SYSTEM FOR CONTROLLING THE MOTION OF ELEOTRIOALLY OPERATED ELEVATORS BY MEANS OF A SWITCH. APPLICATION FILED MAY 21. 1902.

l8 SHEETS-SHEET 9.-

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APPLICATION FILED MAY 21.1902

18 SHEETS-SHEET 10.

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No. 878,496. PATENTED FEB. 11, 1908.

- W. BAXTBR, JR. SYSTEM FOR CONTROLLING THE MOTION OP'EL EGTRIGALLY OPERATED ELEVATORS BY MEANS, OF A SWITCH. APPLIOATIOH FILED MAY 21. 1902.

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No. 878,496. PATENTEDFEB. II, 1908. W. BAXTER, JR. SYSTEM FOR CONTROLLING THE MOTION OF ELEOTRIOALLY OPERATED 1 ELEVATORS BY MEANS OF A SWITCH.

APPLICATION FILED MAY 21, 1902.

' 18 SHEETS-SHEET 12.

FGJ O9. F I G1 08 7 77 WIT INVENTOR ATIYS V No. 878,496. PATENTED FEB. 11, 1908. W. BAXTER, JR.

SYSTEM FOR CONTROLLING THE MOTION OP ELECTRIOALLY OPERATED ELEVATORS BY MEANS OF A SWITCH.

APPLICATION FILED MAY 21,1902.

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I .VVENT OR PATENTED FEB. 11, 1908. W. BAXTBR, JR.

SYSTEM FOR CONTROLLING THE MOTION OE ELEGTRIGALLY OPERATED ELEVATORS BY MEANS OF A SWITCH. APPLICATION FILED MAY 21 1902 18 SHEETS-SHEET .14.

. INVENTOR WI TJVESSES 4W (5 W PATENTED FEB. 11, 1908. W. BAXTBR, JR.

SYSTEM FOR CONTROLLING THE MOTION OP ELEOTRIOALLY OPERATED ELEVATORS BY MEANS OF A SWITCH. APPLIOATION FILED MAY 21. 1902.

18 SHEETS-SHEET 15.

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No. 878,496. PATENTED EEB.11, 1908. W. BAXT E, JR. SYSTEM FOR CONTROLLING TEE MOTION OF'ELECTRIGALLY OPERATED ELEVATORS BY MEANS OF A SWITCH.

APPLICATION FILED MAY 21. 1902.

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18 SHEETS-SHEET 17.

PATENTED FEB. 11, 1908. W. BAXTER, JR. THE MOTION OP BLEGTRIOALLY OPERATED SYSTEM FOR CONTROLLING ELEVATORS BY MEANS OF A SWITCH.

APPLICATION FILED MAY 21.1902.

18 SHBETSSHEET 18.

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[.NVENTOR 1,24% m WITNESSES UNITED STATES PATENT OFFICE.

WILLIAM BAXTER, JR, OF JERSEY CITY, NEW JERSEY.

SYSTEM FOR CONTROLLING THE MOTION OF ELECTRICALLY-OPERATED ELEVATORS BY MEANS OF A SWITCH.

Specification of Letters Patent.

Patented Feb. 1 1,1908.

Application ate m 21.1902. Serial No. 108.378=

To all whom it may concern:

Be it known that I, WILLIAM BAXTER, J r., a citizen of the United States, and a resident of Jersey City, in the county of Hudson and State of New Jersey, have invented a certain new and useful System for Controlling the Motion of Electrically-Operated Elevators by Means of a Switch, of which the following is a specification.

This invention relates to a system for controlling the motion ofelectrically operated elevators by means of a switch which may be located within the moving car, or at any point distant from the elevator machine, from which it is desired to control its operation. It differs from other controlling systems in. that it gives the operator positive control over the motion of the car, and enables him to vary the speed thereof in any manner desired,

within the range of variation of the elevator machine.

when this is placed in the central position,

the car is stopped; while'movement to the right causes the car to run in one direction,

and movement to the leftjcauses the car to run in the other direction.

VVhen the car switch is turned to the active position, either to the right or to the left, it acts to close the circuit connections between the elevator machine motor, and the supply line, and nothing more. As soon as the motor begins to revolve, a switch of some form moves automatically and gradually cuts out the starting resistance in the armature circuit. If any other changes in the circuit connections are required, to bring the motor up to its full velocity, they are effected by the same switch that cuts out the armature re sistance, or by independent switches. The rapidity withwhich these switches move is governed by the use of dash-pots, weights, or springs, or by increasing the magnetizing force'that acts upon the actuating magnets. A common way of increasing the magnetizing force acting on the magnets that operate the switches is to have their coils connected so as to cause the current to increase with the gradual rise in the counter E. M. F. of the motor armature.

.From the foregoing brief explanation, it will be seen that the rate at which the car V speedis accelerated is wholly beyond the conj trol of the. operator in the car, for all he can do is to move the car switch and thereby connect themotor with the supply circuit, and after that the automatically operated switches will accelerate the velocity at a rate that will depend upon their mode of operation, but which in any event is wholly independent of, and incapable of modificationby any effort the car operator may make.

In stopping an elevator operated by the foregoing system, thecar switch is turned to the central positio and this movement disconnects the eleva or motor from the supply circuit and at the same time applies a brake that acts to arrest the motion of the elevator machine. The distance in which the car will stop will evidently depend wholly upon the retarding resistance of the brake, and the driving force of the descending load and the velocity at'which it is moving.,. A little reflection will show that all this system can do is to enable the operator to start and stop the car, but he cannot varyv the rate of acceleration in starting or the rate of retardation in stopping. Furthermore, it is clear that if the car is started with alight load, the acceleration will be rapid, while with a heavy load it will. be slow. is descending with a heavy load at a high velocity, it will traverse a further distance in coming to a stop than if running with a light load and lower speed. Thus it will be seen that in endeavoring to stop at any landing it is uncertain whether the car will stop even with the floor or above or below it. After a considerable amount of experience the 0per-' ator can make a fairly good guess as to the proper instant at which to move the car switch to effect a stop even with the floor, but there is no certainty in the operation, and he often In stopping, if the car that operates the switches that cut out thestarting resistance in the armature circuit, and perform any other operations required to increase the velocity of the motor to the maximum. With this system, the 4 pilot motor can be made to run until it has moved all the switches and has imparted to the elevator motor maximum speed, or it can be armature will at stopped at any" intermediate point, by the simple operation of moving the car switchto a position intermediate between thecentral position and the extreme side position, 7 By this. recess, the operator in the car is given partial control over the rate of acceleration,

and the running speed of the elevator, as he" can throw the car switch to the position that stops the pilot motor whenever, in his judgmerit, the velocity of the car is what itshould be. This, however, brings into play the judgment of thecar operator, and hence is not a means for giving positive control, either of the running speed or of the rate'of acceleration". In stopping, the pilot motor system cannot give the operator any better control over the movement of the car than the first.

named system, because as'it is necessary to be able to stop very quickly, in many cases,

circuit connections must be provided whereby the motor may bestopped without waiting for the pilot motor to rotate afsuflicient number of times to return all the switches to the stop position. Thus the pilot motor through its slowness of action cannot be used to vary the rate of retardation in making stops; I

An elevator controlling system to be perfect'inust be so arranged that it will enable the operator in the car to control the rate of acceleration in starting, tocontrol the velocity when fully under way, and to control the rate of retardation in stopping. The lastnamed feature of more. importance than the first two, because the accuracy with which the elevator car is stopped at landings depends upon it. The elevator controlling system'to be described in what follows aims to fully meet these requirements.

W'hen a direct current constant potential motor is started, .it necessary to introduce resistance in the armature circuit to prevent an excessive flow of current through the armature, owing to the fact that the resistance of the latter is very low. As soon as the armature begins to revolve the counter E, M. F.- it develops opposes the flow of current and thus permits ot the gradual removal of the practical dilliculties, and is therefore objecw tionable, that practically the variations in velocity are etl'ected by introducing resistance in the armature circuit, and by changing the strength of the field. Both these operations can be accomplished. in various creasev ways, but in every instance switches'are required to effect the roper circuit connections, and the contro ler must be made so that when it is actuated, it will move these switches in the proper sequence. If the person who operates the motor stands by the controller, and is able to operate it manually, he can obtain any desired rate of acceleration by advancing the controller handle at the proper rate of speed, and he can obtain any desired retardation rate .by moving the controller handle backward at the proper velocity. If the man who operates the motor is located at a distance from the controller he can obtain the same certainty of control over the operation of the motor if means are rovided whereby he can inove the control or as positively as if his hand were placed upon the operating handle. To accomplish this result all that is necessary is to provide meanswhereby the movement of a handle in the car to a certain position will result in moving the controller'to the corresponding position. Thus if the controller moves over eight steps to cut out the resistance in the armature circuit, 'and to impart to the motor allthe various speeds at which it can run between the slowest and the maximum, the handle in the car should be arrangedto move over eight steps, and when it is moved to the first step it should'cause the controller to move to the first step, and when moved to the second step it should cause the controller to moveto the second step, and so on for every other step.

As it may be. desired in some cases to accelerate the velocity of the car as rapidly as possible to the maximum velocity,'it is necessary that the, controller. beiso constructed that it may be movedrapidly through its entire range of motion. The rapidity with which anotor can be accelerated is limited in practice by the strength to which the armature current Will rise, and this strength is dependent upon the resistance that op oses rotation. It is, evident that if the han le in the elevator car'moves freely, the operator can swing it through its entire range in an interval of time shorter than the minimum time in which the armature velocity can be accelerated. An experienced man would not move the handle. so rapidly, but to guard against blowing out fuses, or throwing the circuit breakers, it is desirable to provide means that will either prevent the operator froinmoving the handle in the car too rap- .idly, or that will prevent the controller from following the movement of the car handle faster than the permissible speed. If the speed retarding device is attached to the controller, thenif the car handle is suddenly thrown over to the last step, the controller will immeclialely move over and will continue to move to the last step, but at a velocity no greater than the retarding devicewill 

